“I hear some people say they are ‘spiritual’ but not ‘religious.’ What do they mean?” — Judy

The place to start is to ask your friends what they mean by this statement. Absent their response here, we can make a few general observations.
Some individuals who say this often are expressing their rejection of “institutional” religion. They may have been burned by an unpleasant church experience or perhaps simply consider themselves above the mundane, human-shaped thing which often passes for “church” in our day. Their critique is not entirely unwarranted — there is plenty of room for improvement if not radical change in the way “church” is done in American culture.
This statement may also reflect a certain self-awareness in which these folks see themselves as generous, hard working, kind and engaged in issues regarding the environment, peace, justice, etc. For them, these character traits carry spiritual import, perhaps even attesting to the presence of “god” within.
Some who say they are “spiritual” are genuine seekers: they possess a yearning for significance and substance that transcends themselves and what they see in this world. They have a genuine interest in the supernatural and want to connect with it in some way.
Interestingly, the Bible does not promote religion; i.e., denominations, theological schools of thought, or church dogma, law and tradition. It does value kindness, generosity, hard work and concern for peace and justice.
The Bible, however, goes beyond these things. It speaks directly to the person who recognizes the substance and value of “spirit.” It affirms man’s innate thirst for something worthy of worship. It offers a glimpse into a holy, righteous God who infinitely transcends man yet who comes to man, offering a life-giving relationship while answering the deepest longing of his heart: unconditional love, belonging, purpose, peace, and eternal life (Jn. 3:16-17; I Cor. 12-13, 15; Phil. 4:4-7).